Accurate computation of input admittance of the antennas on the platform using the advanced delta-gap source model

The gap source model is extensively used in modeling monopole antennas in the method of moments (MOM), due to its simple expression form. But it is not accurate to calculate the input impedance then, the advanced delta-gap source model can solve this problem. Instead of using a shorted-circuited conductor to represent a zero-width exciting gap according to the conventional method, the approach is then set equal to the coaxial fed to estimate the fed position with respect to the working wavelength. Geometry Meshing and the accurate calculation of the impedance matrix elements are applied to the new model to improve the calculation precision. Numerical results are presented to show the high accuracy of the advanced delta-gap source model.